The designers at Josephson use their zest for minutiae, anechoic chambers and a battery of precision instruments to build microphones to tolerances measured in nanometers. They pick dust off components one particle at a time.

Craftsmanship like that does not come cheap. Some Josephson mics cost as much as $7,000, but their owners say they are worth every cent.

Josephson's facilities are located across from a boutique bakery and hair salon in a refurbished industrial area of Santa Cruz, California. The offices resemble a college physics lab and the employees older versions of the students you would find there. Here's a behind-the-scenes look at how some of the world's finest microphones are made.

Above:

The Chamber of Sonic Secrets

Stick your head inside Josephson’s anechoic chamber, a big box that blocks out exterior sound and suppresses echoes, and you will discover that pure silence is the opposite of peaceful.

Like being in pitch darkness, the nearly complete quiet is disorienting, a novel sensation that initiates a kind of instinctual threat assessment. Once you’ve heard nothing, you realize that in normal life you are always hearing something, even if it is an almost imperceptible hum.

From Sound to Heat

The wedges on the chamber’s walls look like a crazy quilt. As the name “anechoic” suggests, they are carefully arranged to eliminate any echoes within the chamber. When struck by sound waves, the individual fibers of the wedges rub together, which converts the sound that would otherwise bounce off the walls into heat.

Technicians use the speaker at the back of the chamber to hit the microphone with sounds from specific angles and determine its response in the absence of any reflected sound or reverberation.

The Ears Know Best

Kelly Kay, a partner in the company, looks at a computer that displays signals from a microphone in the anechoic chamber.

True to the appearance of Josephson’s facility, with its bevy of readouts and gizmos, its design process is largely a matter of math and measurements -- like calculating the acoustic properties of different shapes and materials. But making a good mic also requires a lot of listening and tweaking.

“For some of the aspects of a sound of a microphone there is no measurement for it. It’s easy to make a mic that sounds terrible that has a perfectly flat, textbook performance,” says Kay.

Like Dust in the Vacuum-Hood Wind

Marguerite Power assembles the capsule of a Josephson 700A while seated underneath a dust-removing hood. According to Kay, the company’s 700A and 700S microphones are the hardest ones to build.

"There’s a lot going into them," he says. Kay estimates that each individual 700A takes four to five days' worth of work.

There's a surprising amount of concern over industrial espionage from the otherwise laid-back team at Josephson. One mysterious back room of the facility is off-limits to tours, as Kay claims certain trade secrets may be revealed by a simple photo or description of certain techniques. Despite the fact that other companies can simply buy Josephson mics and disassemble them, Kay says that no amount of reverse engineering can explain how certain components are put together.

Lonely at the Top

The price of the final product reflects the painstaking labor: The 700A retails for $4,600. The stereo 700S, which includes a second microphone capsule, goes for around $7,000.

“If you sort by price, it’s in the top 1 or 2 percent in terms of cost,” says Kay.

While hesitant to name names, Kay says that the bigger companies that used to occupy the high end of the market are trending towards a growing pro-sumer customer base, leaving some room for Josephson to step in with mics like the 700S.

“It’s targeted at the really honest-to-god professional moneymaking engineers who need a tool,” says Kay.

John Vanderslice, owner of the Tiny Telephone recording studio in San Francisco, whose clients include Death Cab for Cutie and Mike Watt, is one such professional. He describes the 700A as an “incredibly hi-fi, beautiful-sounding microphone.”

No Name-Dropping

Scott Solter, a recording engineer whose credits include indie-rock giants such as Spoon and the Mountain Goats, has recorded some of his sessions using Josephson mics almost exclusively.

“I’d use all the A-words: They are awesome, amazing, ass-kicking,” he says. As for the e22S and C617 models: “There is something about the openness of those mics, I could use them without any thought or concern.”

Though many music professionals are eager to discuss Josephson’s products, Kelly Kay is cagey about who exactly buys his mics.

“Sadly, once you get in our niche you don’t want to drop names of the customers," says Kay. "In our echelon of making stuff you have a choice of dropping the names of people, and then they right away expect to have endorsement type things and get deals on stuff. We try and make a top-notch product, with the best value, that somebody who really is on the highest echelon is happy paying full price for.”

The plan appears to be working. Producers and studio owners rave about the company’s products. Vanderslice is emphatic in his praise: “I own 10 Josephson mics now.... Those are not discounted. I don’t have an endorsement from them.”

This willingness to pay full price even extends to Steve Albini, the legendary engineer and producer whose studio, Electrical Audio, is a trendsetter in recording technology. Albini not only purchases from Josephson, he actually commissioned the company to design a mic, the e22S, and helped test and refine it. Says Kay, "The mic didn’t actually exist, and he talked to Dave Josephson about 'could you make this?’"

Despite his contribution to bringing the e22S into existence, and his advocacy of Josephson products in general, even Albini isn’t asking for a discount.

“He’s used these mics, which he’s paid for, pretty much every session,” Kay reports proudly.

Double Standards

David Josephson, the eponymous founder of Josephson Engineering, is a professorial type who enunciates his words with Oxonian exactitude. His diction seems appropriate -- and probably not coincidental -- to his chosen career as a designer of precision recording instruments.

According to Josephson, the quality of microphones at the lower end of the price spectrum can vary widely, even within the same brand and model. So if one buys two of the same brand new microphone, they could sound noticeably different. It's the luck of the draw. Even more so with two similarly spec'd microphones from different brands.

That's why exacting standards are Josephson's thing. And he is not only a practitioner but an evangelist.

“There is an international standard for measuring the performance of microphones,” he says. “There isn’t a single microphone company in the world that is completely compliant with that standard.”

As chairman of the Audio Engineering Society's Standards Committee Working Group on Microphones, he has spent years trying to get convergence on a global standard for testing and comparison. "We might get there,” he says.

The goal of creating a battery of tests that is truly representative of a mic’s performance would allow end users to make an informed comparison of the products on the market. However, Josephson and Kay add that they do not publish the technical specifications for their most expensive mics, and report that customers almost never ask for that information.

People who buy the top-end mics “just want the mic in their hands; they want to use it,” says Kay. Josephson adds, “Our lowest-cost microphone has a frequency response on the data sheet, our more expensive mics don’t.” John Vanderslice, owner of studio Tiny Telephone, echoes that sentiment, saying that he pays almost no attention to the data sheets that come with many of the microphones he owns.

Josephson's engineers embrace two competing design philosophies. Any element of a microphone that can be measured, they measure, preferably at nano-scale. Yet they say it is easy to build a mic that has excellent specs and terrible performance. Good sound is ineffable, they argue, and no readouts or equations will get you there.

Though Kay and Josephson stress that scientific testing ensures all their mics meet a consistent standard, it is clearly about more than quality control. To an outsider, they seem torn between two muses, math and music, and there is a whiff of fetishism in their obsession with technical details.

But perhaps they see no dichotomy, finding mysticism in numbers and precision in listening.